The only difference here is that while Ubisoft succeeded (so far) at keeping (fully playable) pirated copies from surfacing, EA has not. If you look around, you will even find a scene release of C&C4 which from what I read, uses a server emulator to handle all the basic requests/calls made by the C&C4 game client. Assassin's Creed 2 on the other hand has the DRM integrated into the maps and mission data thereby making it far more tedious and time consuming to crack.
This suggests that EA did not implement the DRM nearly as well as Ubisoft. Not only that, but with Ubisoft's DRM, your game will literally save-state if the connection drops so you can pick up where you left off. You don't lose any progress whatsoever (I've even had the game crash to desktop from a Vsync bug and I didn't lose any progress since auto-saving is so frequent). This really makes EA's DRM seem like a "cheap knockoff" of what Ubisoft has done.
As long as we're going to reinvent the wheel again, we might as well try making it round this time. - Mike Dennison